OFFSET
0,2
COMMENTS
Number of steps needed to reach zero when starting from k = 2*n + 1 and repeatedly applying the map that replaces k by k - d(k), where d(k) is the number of divisors of k (A000005).
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = A155043(2*n + 1).
MATHEMATICA
Table[Length[NestWhileList[#-DivisorSigma[0, #]&, n, #!=0&]]-1, {n, 1, 200, 2}] (* Harvey P. Dale, Aug 31 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 02 2015
STATUS
approved